Cytology interpretation after a change to HPV testing in primary cervical screening: Observational study from the English pilot.

BACKGROUND: Overcalling of abnormalities has been a concern for using cytology triage after positive high-risk human papillomavirus (HPV) tests in cervical screening. METHODS: The authors studied the detection of cytological and histological abnormalities at age 24 to 64 years, using data from the English HPV pilot. The pilot compared routine implementation of primary cervical screening based on cytology (N = 931,539), where HPV test results were not available before cytology reporting, with that based on HPV testing (N = 403,269), where cytology was only required after positive HPV tests. RESULTS: Revealed HPV positivity was associated with a higher direct referral to colposcopy after any abnormality (adjusted odds ratio [ORadj ], 1.16; 95% confidence interval [CI], 1.14-1.18). Laboratories with higher direct referral referred fewer persistently HPV-positive women after early recall. The detection of high-grade cervical intraepithelial neoplasia (CIN2+) after direct referral increased with an ORadj of 1.17 (95% CI, 1.13-1.20) for informed versus uninformed cytology. Generally, the positive predictive value (PPV) of colposcopy for CIN2+ remained comparable under both conditions of interpreting cytology. In women 50 to 64 years old with high-grade dyskaryosis, however, the PPV increased from 71% to 83% after revealing HPV positivity (ORadj , 2.05; 95% CI, 1.43-2.93). CONCLUSIONS: Quality-controlled cervical screening programs can avoid inappropriate overgrading of HPV-positive cytology.